Researchers have found that food-poisoning bacteria, Listeria monocytogenes, can hide inside romaine lettuce.
That means that surface cleansing and disinfecting procedures won’t kill the nasty bacteria that is particularly risky for the very young, the very old and people with compromised immune systems.
A team at Purdue University in Indianna, led by Amanda Deering, clinical assistant professor in the Department of Food Science, showed that the bacteria could live within lettuce in every stage of the plant growth process, residing inside the plant tissue.
L. monocytogenes can gain entry into the plant through cracked seed coats, small tears in root tissue during germination and damaged plant tissue. The researchers found that exposing lettuce to the bacteria could lead to infection of plant tissue in as little as 30 minutes.
“Knowing this can happen, we need to keep it on our radar as we continue to follow good agricultural practices,” Deering said.
L. monocytogenes can also cross the placental barrier in pregnant women, which can trigger a miscarriage.
“For immune-compromised consumers, it’s important to remember, that canned or cooked produce is better,” Deering said.
This bacteria thrives in cool temperatures which are sometimes used to fight other food-poisoning strains of bacteria. Heat kills them all.